PURPURA. 385 



once, but took their time in coming out, according to their 

 individual dispositions; doubtless the quick-minded and 

 more curious commencing their travels first, whilst those of 

 slow and studious constitutions would remain as long as a 

 fortnight before resolving to see the world, which, with 

 young PurpureE, is no very dangerous adventure, since the 

 neighbouring barnacles enable them to look about with 

 safety, before making a long journey from their birth-place.* 



When the Purpura grows up, it makes its constant 

 residence in rocks and stones in the middle sub-region of 

 the littoral zone, inhabiting that part of the space between 

 tide-marks, in which Fucus articulatus is the charac- 

 teristic seaweed, when it is the companion everywhere of 

 Littorina Uttorea and Patella vulgata, and on the west 

 coast finds itself in company with Trochus umbilicatus, 

 on the south with. Trochus lineatus, all of which, if they 

 had a vote in the matter, would prefer its room to its 

 company, for it is extremely voracious, and when it 

 gets hold of a neighbouring Mollusk, seldom leaves it 

 before at least attempting to swallow it. We have seen 

 a Purpura devour a periwinkle in the course of an after- 

 noon when placed in the same vessel of sea-water, sucking 

 its prey as it were out of the shell, after placing the orifice 

 of its own body-case against that of its victim. It per- 

 forates shells sometimes also, probably, as Mr. Hancock 

 suggested, by means of its armed tongue. We have a 

 sketch in our possession, drawn by Mr. Spence Bate, of a 

 Purpura devouring a mussel. " The whelk," writes our 

 valued correspondent, " attacked the mussel, but it bored 

 where there was no epidermis. I pulled it off, and turned 

 the mussel upside down (the other valve having more 

 epidermis upon it), but in a short time I returned and 

 * Peach in Aimala Nat. Hist. vol. xi. p. 29. 



VOL. III. 3 1) 



